This invention relates to a process for producing partially esterified metal salts of sulfoisophthalic acid solutions in a glycol and to a process for producing a polymer comprising repeat units derived from sulfoisophthalic acid or salt thereof or ester thereof, a carbonyl compound, and a glycol in which a phosphorus compound can be used to improve polymer properties.
Polyesters are widely used to manufacture textile fibers and bottle resins and can be manufactured by combining a glycol such as ethylene glycol and a carbonyl compound such as dimethyl terephthalate (DMT) or terephthalic acid (TPA). For example, DMT reacts with a glycol such as ethylene glycol to form bis-glycolate ester of terephthalate (xe2x80x9cmonomerxe2x80x9d) in the ester exchanger column. The monomer is polymerized by condensation reactions in one or two prepolymerizers and then a final polymerizer or finisher. TPA can be combined with ethylene glycol to form a slurry at 60 to 80xc2x0 C. followed by injecting the slurry into an esterifier. Linear oligomer with degree of polymerization less than 10 is formed in one or two esterifiers (first and second, if two) at temperatures from 240xc2x0 C. to 290xc2x0 C. The oligomer is then polymerized in one or two prepolymerizers and then in a final polymerizer or finisher at temperatures from 250xc2x0 C. to 300xc2x0 C.
Additives such as catalysts, stabilizers, delusterants, and toners are often added to the TPA slurry before the esterifier, in the esterifier, or in the oligomer before the prepolymerizer. Commercial polyester processes commonly use antimony compounds as polycondensation catalyst and phosphorous compounds as stabilizers. See generally, Encyclopedia of Chemical Technology, 4th edition, John Wiley, New York, 1994, Volume 10, pages 662-685 and Volume 19, pages 609-653.
However, it is difficult to incorporate a dye material into or onto these polyesters. Therefore, copolymers comprising repeat units derived from terephthalic acid, sulfoisophthalic acid, and glycol are widely used because they can be used to make fibers dyeable by basic dyes or polyester hydrolyzable in water. Such copolymers are referred to as cationic dyeable (CD) polyesters and can be produced by adding small amounts of a sulfonated isophthalate metal salt or its ester such as, for example, sodium dimethylsulfoisophthalate (Na-DMSIP) powder to the ester exchanger of DMT process. Fiber made from CD copolymer gives brilliant shades on dyeing with basic/cationic dyes and also dyes with disperse dyes to deeper shades.
U.S. Pat. No. 5,559,205 discloses a process for adding fully esterified bis(2-hydroxyethyl) sodium 5-sulfoisophthalate (Na-SIPEG) or bis(2-hydroxyethyl) lithium 5-sulfoisophthalate (Li-SIPEG) to the monomer line of DMT process, or oligomer line or the second esterifier of TPA process to make cationic dyeable polyesters.
U.S. Pat. No. 6,075,115 discloses a process for making Na-SIPEG solution and Li-SIPEG solution from sodium 5-sulfoisophthalic acid (Na-SIPA) and to, lithium 5-sulfoisophthalic acid (Li-SIPA) powder. In order to fully esterify the Na-SIPA and Li-SIPA, special titanium catalyst was used, which comprises (1) a titanium compound, a solubility promoter, a phosphorus source, and optionally a solvent, or (2) a titanium compound, a complexing agent, a phosphorus source, and optionally a solvent, a sulfonic acid. The fully esterified Na-SIPEG and LiSIPEG solutions were manufactured by a vendor and then shipped to polyester producers. The solution was then injected into the monomer line of DMT process, or oligomer line or the second esterifier of TPA process to make copolyesters.
These processes have several disadvantages including (1) high cost of 20% Na-SIPEG solution and 20% Li-SIPEG solution, because a separate facility is required to make these solutions from Na-SIPA or Li-SIPA powder and glycol; (2) high transportation cost for the 20% solutions; (3) high investment cost to build a heated storage tank, pump, and piping system for the 20% solutions; (4) cationic dyeable polyester producers cannot control the properties of the solutions such as DEG (diethylene glycol), acidity, carboxyl groups, and concentration; and (5) a tendency to form dimer and/or trimer in the solutions.
Therefore, there is a need to develop a process to produce a partially esterified Na-SIPA solution and Li-SIPA solution that is more stable and less likely to form solids when cooled to room temperature, especially at high concentrations. An advantage of the invention is that the partially esterified Na-SIPA and Li-SIPA solutions can be made immediately before it is used in producing polyester thereby significantly reducing manufacturing and transportation cost. Another advantage is that the unesterified carboxyl groups partially accelerate the polycondensation reaction thereby improving productivity. Also an advantage is that the properties of the solution can be better controlled. A further advantage is that less dimer, trimer, or tetramer is produced rendering a more stable Na-SIPA or Li-SIPA solution and more uniform basic dye site distribution in the resulting polymer.
Additionally, it is well known that phosphoric acid is commonly used to control the discoloration of polyester homopolymer, but phosphoric acid does not improve the color of copolymer derived from terephthalic acid and sulfoisophthalic acid. Thus, there is also a need to develop a process using a nonacidic phosphorus compound to improve the color of dyeable polyester.
Furthermore, stainless steel or carbon steel is commonly used as surface metal of process equipment, such as heat exchanger, for commercial production of a polymer having repeat units derived from an alkali metal SIPA. An alkali metal SIPA prepolymer formed during the production was found to stick on the metal surface of the process equipment degrading or carbonizing into black solids and, subsequently, resulting in process plugging, which requires shutdown every 1 to 4 months to clean the plugged tubes. Therefore, it is also a need to identify process equipment for producing a polymer having repeat units derived from an alkali metal SIPA.
A process that can be used for producing a partially esterified SIPA in a first glycol is disclosed. The process comprises contacting a SIPA to produce a mixture and heating the mixture under a condition sufficient to partially esterify the SIPA wherein the mixture optionally comprises a catalyst.
Also disclosed is a process that can be used for controlling the color of a dyeable polyester. The process comprises contacting, optionally in the presence of a phosphorus compound and/or a catalyst, a SIPA or partially esterified SIPA with either (a) a polymerization mixture comprising a carbonyl compound and a second glycol or (b) an oligomer derived from a carbonyl and a second glycol.
Further disclosed is a process for producing a dyeable polyester. The process comprises contacting, optionally in the presence of a phosphorus compound and/or a catalyst, a SIPA or partially esterified SIPA with either (a) a polymerization mixture comprising a carbonyl compound and a second glycol or (b) an oligomer derived from a carbonyl and a second glycol wherein the process is carried out in a vessel or process equipment having nickel or a nickel alloy as surface metal or fluoropolymer as a surface.
The acronym xe2x80x9cSIPAxe2x80x9d used herein can have the formula of (RO(O)C)2ArS(O)2OM in which each R can be the same or different and is hydrogen or an alkyl group containing 1 to about 6 carbon atoms or hydroxyalkyl group containing 1 to 6 carbon atoms; Ar is a phenylene group; and M is hydrogen, an alkali metal, an alkaline earth metal, quaternary ammonium or phosphonium, or combinations of two or more thereof. The preferred M is an alkali metal such as lithium or sodium. Accordingly, SIPA, unless otherwise specifically indicated, can also include those that are partially or fully esterified.
As such, xe2x80x9cSIPAxe2x80x9d, unless otherwise specifically indicated, can collectively refer to 5-sulfoisophthalic acid, alkali metal salt of 5-sulfoisophthalic acid, an ester of 5-sulfoisophthalic acid, an ester of alkali metal salt of 5-sulfoisophthalic acid, or combinations of two or more thereof. For example, Na-SIPA and Li-SIPA are referred to, because they are specifically indicated, sodium 5-sulfoisophthlalic acid and lithium 5-sulfoisophthlalic acid, respectively. Also, for example, specifically indicated Na-DMSIP refers to sodium dimethyl 5-sulfoisophthalate. Further, for example, specifically indicated Na-SIPEG and Li-SIPEG refers to fully esterified sodium 5-sulfoisophthalate and fully esterified lithium 5-sulfoisophthalate, respectively, in ethylene glycol; specifically indicated Na-SIPPG and Li-SIPPG refers to fully esterified sodium 5-sulfoisophthalate and fully esterified lithium 5-sulfoisophthalate, respectively, in propylene glycol (1,3-propanediol).
Similarly, the term xe2x80x9cpartially esterified SIPAxe2x80x9d used herein, unless otherwise specifically indicated, refers to partially esterified 5-sulfoisophthalic acid, partially esterified alkali metal salt of 5-sulfoisophthalic acid, an ester of partially esterified 5-sulfoisophthalic acid, an ester of partially esterified alkali metal salt of 5-sulfoisophthalic acid, or combinations of two or more thereof. The term xe2x80x9cpartially esterifiedxe2x80x9d used herein, unless otherwise indicated, refers to esterifcation of about 30% to about 99%, preferably about 50% to about 99%, and most preferably 80% to 95%, by mole, of the total carboxyl groups of SIPA. Any alkali metal SIPA powder can be used. The preferred alkali metal SIPA is Li-SIPA, Na-SIPA, or combinations thereof.
Examples of SIPA include, but are not limited to, 5-sulfoisophthalic acid; alkali metal salt of 5-sulfoisophthalic acid such as sodium 5-sulfoisophthalic acid (Na-SIPA), lithium 5-sulfoisophthalic acid (Li-SIPA); a mono- or di-ester of 5-sulfoisophthalic acid; a mono- or di-ester of alkali metal salt of 5-sulfoisophthalic acid such as bis(2-hydroxyethyl) sodium 5-sulfoisophthalate (Na-SIPEG), bis(2-hydroxyethyl) lithium 5-sulfoisophthalate (Li-SIPEG), sodium dimethyl 5-sulfoisophthalate (Na-DMSIP), lithium dimethyl 5-sulfoisophthalate (Li-DMSIP), bis(3-hydroxypropyl) sodium 5-sulfoisophthalate (Na-SIPPG), bis(3-hydroxypropyl) lithium 5-sulfoisophthalate (Li-SIPPG), and combinations of two or more thereof.
According to the invention, the term xe2x80x9cglycolxe2x80x9d is interchangeable with xe2x80x9calcoholxe2x80x9d. Any glycol that can esterify SIPA can be used as the first glycol of the invention. The preferred glycol can have 1 to about 10, preferably 1 to about 8, and most preferably 1 to 4 carbon atoms per molecule such as, for example, an alkylene glycol, a polyalkylene glycol, polyoxyalkylene glycol, or combinations thereof. Examples of suitable glycols include, but are not limited to, ethylene glycol, propylene glycol, isopropylene glycol, butylene glycol, 1-methyl propylene glycol, pentylene glycol, diethylene glycol, triethylene glycol, polyethylene glycols, polyoxyethylene glycols, polyoxypropylene glycols, polyoxybutylene glycols, and combinations of two or more thereof. The presently most preferred glycol is an alkylene glycol such as ethylene glycol or 1,3-propanediol for the polyester produced therefrom has a wide range of industrial applications.
An alkali metal SIPA can be combined with a glycol in any suitable manner and in any suitable container, vessel, or reactor to produce an alkali metal SIPA-glycol mixture. The quantity of the metal SIPA can be any quantity so long as the quantity can produce a desired partially esterified alkali metal SIPA. Generally, based on total weight of the alkali metal SIPA-glycol mixture, the metal SIPA can be present in the range of about 5% to about 70%, preferably about 10% to about 50%, and most preferably 20% to about 40% by weight.
A metal salt such as sodium acetate or lithium acetate dihydrate can be added to the alkali metal SIPA-glycol mixture in the amount of about 0.2 to about 200 g, preferably 2 to 20 g, per kg alkali metal SIPA to control the formation of diethylene glycol. The metal SIPA-glycol mixture in slurry form can be heated at about 60xc2x0 C. to about 250xc2x0 C., preferably about 100xc2x0 C. to about 200xc2x0 C., and most preferably 140xc2x0 C. to 190xc2x0 C. for at least about 5 minutes, preferably about 1 to about 4 hours. Water is a by-product. Water and glycol vapor can be condensed in a condenser or discharged in the air, or flow to a water separation column. Thereafter, the resulting solution can be further heated at the same or lower temperature. The solution, whether further heated or not, can be directly used in a process for producing polyester such as, for example, being injected into the monomer line or prepolymerizer of DMT process, or the oligomer line or the second esterifier or prepolymerizer of TPA process discussed in the BACKGROUND OF THE INVENTION.
Optionally, a catalyst such as a titanium-containing compound can be introduced into the metal SIPA-glycol mixture slurry (before, during or after the slurry is heated) or solution (while solution is being formed or continually heated or cooled). If a catalyst is introduced before or during the heating, it can accelerate the esterification reaction. The catalyst can also accelerate polycondensation reaction unless it is deactivated by an inhibitor. Other catalysts such as cobalt, antimony, manganese, or zinc catalyst commonly employed in the manufacture of polyester can also be used. The description of these catalysts is omitted herein because such catalyst is well known to one skilled in the art.
The preferred titanium compounds used in the process are organic titanium compounds such as, for example, titanium tetrahydrocarbyloxides, also referred to as tetraalkyl titanates herein for they are readily available and effective. Examples of suitable titanium tetrahydrocarbyloxides include those having the formula of Ti(OR1)4 where each R1 is individually selected from an alkyl, cycloalkyl, alkaryl, hydrocarbyl radical containing from 1 to about 30, preferably 2 to about 18, and most preferably 2 to 12 carbon atoms per radical and each R1 can be the same or different. Titanium tetrahydrocarbyloxides in which the hydrocarboxyl group contains from 2 to about 12 carbon atoms per radical which is a linear or branched alkyl radical are most preferred because they are relatively inexpensive, more readily available, and effective in forming the solution. Suitable titanium tetrahydrocarbyloxides include, but are not limited to, titanium tetraethoxide, titanium tetrapropoxide, titanium tetraisopropoxide, titanium tetra-n-butoxide, titanium tetrahexoxide, titanium tetra 2-ethylhexoxide, titanium tetraoctoxide, and combinations of two or more thereof. The titanium tetrahydrocarbyloxides are well known to one skilled in the art. See, for example, U.S. Pat. Nos. 6,066,714 and 6,166,170, the description of which is incorporated herein by reference. Examples of commercially available organic titanium compounds include, but are not limited to, TYZOR(copyright) TPT and TYZOR(copyright) TBT (tetra isopropyl titanate and tetra n-butyl titanate, respectively) available from E. I. du Pont de Nemours and Company, Wilmington, Del., U.S.A.
A titanium-containing composition can be produced by any means known to one skilled in the art such as those disclosed in U.S. Pat. Nos. 6,066,714 and 6,166,170 discussed above and description of which is omitted herein for the interest of brevity.
A titanium-containing composition can also include, but are not limited to, a titanium solution made from a titanium compound disclosed above and a glycol disclosed above, in the presence of a phosphorus compound. Any phosphorus compound that can stabilize a titanium-glycol solution, i.e., can prevent the solution from gelling or precipitation, can be used. Any phosphorus compound that, when used with a polyester catalyst, produces polyester having low yellowness, as compared to a polyester produced from a catalyst without such phosphorus compound, can be used. Examples of suitable phosphorus compounds include, but are not limited to, a polyphosphoric acid or a salt thereof, a phosphonate ester, a pyrophosphoric acid or salt thereof, a pyrophosphorous acid or salt thereof, and combinations of two or more thereof. The polyphosphoric acid can have the formula of Hn+2PnO3n+1 in which n is xe2x89xa72. The phosphonate ester can have the formula of (R2O)2P(O)ZCO2R2 in which each R2 can be the same or different and can be independently H, C1-4 alkyl, or combinations thereof; and Z is C1-5 alkylene, C1-5 alkylidene, or combinations thereof, di(polyoxyethylene)hydroxymethyl phosphonate, and combinations of two or more thereof. The salt can be an alkali metal salt, alkaline earth metal salt, ammonium salt, or combinations of two or more thereof.
Illustrative examples of suitable phosphorus compounds include, but are not limited to, potassium tripolyphosphate, sodium tripolyphosphate, potassium tetra phosphate, sodium pentapolyphosphate, sodium hexapolyphosphate, potassium pyrophosphate, potassium pyrophosphite, sodium pyrophosphate, sodium pyrophosphate decahydrate, sodium pyrophosphite, ethyl phosphonate, propyl phosphonate, hydroxymethyl phosphonate, di(polyoxyethylene)hydroxymethyl phosphonate, methylphosphonoacetate, ethyl methylphosphonoacetate, methyl ethylphosphonoacetate, ethyl ethylphosphonoacetate, propyl dimethylphosphonoacetate, methyl diethylphosphonoacetate, triethyl phosphonoacetate, or combinations of two or more thereof.
For example, a titanium-containing catalyst can contain a salt of a polyphosphoric acid disclosed above, having 0.001% to 10% titanium, 50% to 99.999% glycol, and 0% to 50% water, all weight % in which the molar ratio of phosphorus to titanium is about 0.001:1 to 10:1.
The catalyst can further comprise a cocatalyst. Examples of cocatalysts include, but are not limited to, cobalt/aluminum catalysts, antimony compounds, and combinations thereof. The cobalt/aluminum catalyst comprises a cobalt salt and an aluminum compound in which the mole ratio of aluminum to cobalt is in the range of from 0.25:1 to 16:1. The cobalt/aluminum catalyst is disclosed in the U.S. Pat. No. 5,674,801, disclosure of which is incorporated herein by reference.
Optionally, de-foaming agent such as, for example, polydimethylsiloxane (or its emulsion or solution) can be introduced into the metal SIPA-glycol mixture slurry (before, during or after the slurry is heated) or solution (while solution is being formed or continually heated or cooled). The de-foaming agent can reduce surface tension thereby preventing the slurry or solution from foaming and stabilizing the subsequent polycondensation process, if the solution is used for producing polyester. Because the de-foaming agents are so well known to one skilled in the art, the description is omitted herein in the interest of brevity.
According to another embodiment of the invention, a process comprises contacting, optionally in the presence a phosphorus compound and/or a catalyst, either (a) a SIPA or partially esterified SIPA with a polymerization mixture comprising a carbonyl compound and a second glycol or (b) a SIPA or partially esterified SIPA with an oligomer derived from a carbonyl and a second glycol.
The phosphorus compound, catalyst, and partially esterified SIPA can be the same as those disclosed above and the disclosures of which are incorporated here. The second glycol can be the same or different from the first glycol and can include those disclosed above for the first glycol. The presently preferred second glycols are ethylene glycol and 1,3-propanediol.
According to the invention, the phosphorus compound can be present in the process before, during, or after a carbonyl compound or ester thereof is esterified or transesterified. Similarly, it can be present before, during, or after the polycondensation stage. The phosphorus compound can be used to inhibit the catalytic activity of a titanium-containing catalyst or other catalysts or trace elements such as manganese, cobalt, zinc, aluminum, iron, lead, silicon, to reduce the discoloration of polyester produced using a titanium-containing catalyst or other catalysts or trace elements, or both. The phosphorus compound can be mixed with the catalyst, such as titanium, antimony, manganese, zinc, before the catalyst is introduced to the polyester reaction process. Alternatively, the phosphorous compound can be introduced to the process separately before or after the catalyst is introduced.
For example, in a TPA process, a titanium catalyst, alone or with other catalysts such as antimony can be used as polycondensation catalyst for an oligomer. Alternatively, a titanium-containing catalyst can be present in the ester exchanger to accelerate transesterification reaction or in the esterifier to accelerate the esterification reaction. Generally, titanium-containing catalyst is more active in polycondensation reaction than in esterification or transesterification. The proper level of titanium-containing catalyst for esterification or transesterification can be an excess level for polycondensation. When titanium-containing catalyst presented in the esterifier or ester exchanger (transesterifier) is an excess for polycondensation, or when polycondensation is intended with a non titanium-containing catalyst such as antimony, part of or all of the titanium catalyst is preferably deactivated or inhibited after esterification or transesterification with phosphoric acid or the phosphorus compounds (change only if you exclude phosphoric acid above) disclosed above, to avoid discoloration of the polymer.
The titanium-containing catalyst present in the polymer can cause increased degradation and yellowness in the future processing. Part of or all of the titanium catalyst can be deactivated or inhibited after polymerization with a phosphorus compound disclosed, to avoid discoloration of the polymer.
Similarly, when manganese, zinc, cobalt, aluminum, silicon, or other catalysts are used as esterification or transesterification catalyst and titanium-containing catalyst is used as polycondensation catalyst, these catalysts can be deactivated by the presence of a phosphorous compound disclosed above.
Any carbonyl compound, which when combined with a glycol, can produce a polyester can be used. Such carbonyl compounds include, but are not limited to, acids, esters, amides, acid anhydrides, acid halides, salts of carboxylic acid oligomers or polymers having repeat units derived from an acid, or combinations of two or more thereof. The presently preferred acid is an organic acid such as a carboxylic acid or salt thereof. The oligomer of a carbonyl compound such as TPA and glycol generally has a total of about 2 to about 100, preferably from about 2 to about 20 repeat units derived from the carbonyl compound and glycol.
The organic acid or ester thereof can have the formula of R3COOR3 in which each R3 independently can be (1) hydrogen, (2) hydrocarboxyl radical having a carboxylic acid group at the terminus, or (3) hydrocarbyl radical in which each radical has 1 to about 30, preferably about 3 to about 15 carbon atoms per radical which can be alkyl, alkenyl, aryl, alkaryl, aralkyl radical, or combinations of two or more thereof. The presently preferred organic acid or ester thereof has the formula of R3O2CACO2R3 in which A is an alkylene group, an arylene group, alkenylene group, or combinations of two or more thereof and R2 is the same as above. Each A has about 2 to about 30, preferably about 3 to about 25, more preferably about 4 to about 20, and most preferably 4 to 15 carbon atoms per group. Examples of suitable organic acids include, but are not limited to, terephthalic acid, isophthalica acid, napthalic acid, succinic acid, adipic acid, phthalic acid, glutaric acid, oxalic acid, maleic acid, and combinations of two or more thereof. Examples of suitable esters include, but are not limited to, dimethyl adipate, dimethyl phthalate, dimethyl terephthalate, dimethyl glutarate, and combinations of two or more thereof.
The presently preferred organic diacid is terephthalic acid or its ester dimethyl terephthalate because the dyeable polyesters produced therefrom have a wide range of industrial applications.
The contacting of the carbonyl compound and glycol in the presence of the catalyst can be carried out by any suitable means.
Any suitable condition to effect the production of a polyester can include a temperature in the range of from about 150xc2x0 C. to about 500xc2x0 C., preferably about 200xc2x0 C. to about 400xc2x0 C., and most preferably 250xc2x0 C. to 300xc2x0 C. under a pressure in the range of from about 0.001 to about 1 atmosphere for a time period of from about 0.2 to about 20, preferably about 0.3 to about 15, and most preferably 0.5 to 10 hours.
The molar ratio of the glycol to carbonyl compound can be any ratio so long as the ratio can effect the production of an ester or polyester. Generally the ratio can be in the range of from about 1:1 to about 10:1, preferably about 1:1 to about 5:1, and most preferably 1:1 to 4:1. The CD polyester produced by the invention process can comprise about 1 to about 200 parts per million by weight (ppm) of titanium and about 1 to about 200 ppm, preferably about 5 to about 100 ppm, of phosphorus. If two or more carbonyl compounds are employed, the molar ratio of the second or third carbonyl compound to the first carbonyl compound can each be in the range of from about 0.0001:1 to about 1:1. For example, a dyeable polyester can comprise 85 mole % to 99.9 mole % of repeat units derived from terephthalic acid or terephthalate and 0.1 mole % to 15 mole % of repeat units derived from sodium 5-sulfoisophthalic acid or lithium 5-sulfoisophthalic acid.
As disclosed above, the catalyst can be a cobalt, antimony, manganese, or zinc catalyst commonly employed in the manufacture of polyester. A preferred antimony compound can be any antimony compound that is substantially soluble in a solvent disclosed above. Examples of suitable antimony compounds include, but are not limited to, antimony oxides, antimony acetate, antimony hydroxides, antimony halides, antimony sulfides, antimony carboxylates, antimony ethers, antimony glycolates, antimony nitrates, antimony sulfates, antimony phosphates, and combinations of two or more thereof. The catalyst, expressed as element Co, Sb, Mn, Zn, or Ti, Al, Si, can be present in the range of about 0.001 to about 30,000 ppm of the medium comprising the carbonyl compound and glycol, preferably about 0.1 to about 1,000 ppm, and most preferably 1 to 100 ppm by weight. A cocatalyst, if present, can be in the range of from about 0.01 to about 1,000 ppm of the reaction medium.
The invention process can also be carried out using any of the conventional melt or solid state techniques and in the presence or absence of a toner compound to reduce the color of a polyester produced. Example of toner compounds include, but are not limited to, cobalt aluminate, cobalt acetate, Carbazole violet (commercially available from Hoechst-Celanese, Coventry, R.I., U.S.A., or from Sun Chemical Corp, Cincinnati, Ohio, U.S.A.), Estofil Blue S-RLS(copyright) and Solvent Blue 45(trademark) (from Sandoz Chemicals, Charlotte, N.C., U.S.A), CuPc Blue (from Sun Chemical Corp, Cincinnati, Ohio, U.S.A.). These toner compounds are well known to one skilled in the art and the description of which is omitted herein. The toner compound can be used with the catalyst disclosed herein in the amount of about 0.1 ppm to 1000 ppm, preferably about 1 ppm to about 100 ppm, based on the weight of polyester produced.
The invention process can also be carried out using any of the conventional melt or solid state techniques and in the presence or absence of an optical brightening compound to reduce the yellowness of the polyester produced. Example of optical brightening compounds include, but are not limit to, 7-naphthotriazinyl-3-phenylcoumarin (commercial name xe2x80x9cLeucopure EGMxe2x80x9d, from Sandoz Chemicals, Charlotte, N.C., U.S.A.), 4,4xe2x80x2-bis(2-benzoxazolyl) stilbene (commercial name xe2x80x9cEastobritexe2x80x9d, from Eastman Chemical, Kingsport, Tenn., U.S.A). These optical brightening compounds are well known to one skilled in the art and the description of which is omitted herein. The optical brightening compound can be used with the catalyst disclosed herein in the amount of about 0.1 ppm to 10000 ppm, preferably about 1 ppm to about 1000 ppm, based on the weight of polyester produced.
According to a further embodiment of the invention, a process for producing a dyeable polyester is provided. The process comprises contacting either (a) a SIPA or partially esterified SIPA with a polymerization mixture comprising a carbonyl compound and a second glycol or (b) a SIPA or partially esterified SIPA with an oligomer derived from a carbonyl and a second glycol. The process is carried out in a vessel (or container or reactor) having nickel or a nickel alloy as surface metal or fluoropolymer as surface and can be carried out in the presence of a catalytic amount of a catalyst and a phosphorus compound. The glycol, catalyst, phosphorus compound, carbonyl compound, partially esterified alkali metal 5-sulfoisophthalic acid, and process conditions can be the same as those disclosed above.
Generally a nickel-surfaced vessel or process equipment can comprise nickel metal, Ni 99 to 100%. A nickel alloy-surfaced vessel or process equipment can comprise by weight: Ni, 25 to 85%; Mo, 0 to 30%; Fe, 0 to 50%; Cu, 0 to 33%; Cr, 0 to 24%; Si, 0 to 10%; and other elements such as Mn, Ti, Al, Co, W, Cb, V, Ta, P, S, 0 to 5% each. The following are examples of commercially available nickel and nickel alloys commercially available in the U.S.A. Composition is by weight, trace metals of less than 0.9% were not listed in composition. Nickel 200 and Nickel 201 (Ni 99.5%), Hastelloy B (Ni 61.0%, Mo 28.0%, Fe 5.5%, Co 2.5%, Cr 1.0%, Si 1.0%, Mn 1.0%), Hastelloy D (Ni 82.0%, Si 9.25%, Cu 3.0%, Fe 2.0%, Co 1.5%, Cr 1.0%, Mn 0.9%, Co 1.25%, Cb 2.1%), Hastelloy C-276 (Ni 57.0%, Mo 16.0%, Fe 5.5%, W 3.75%, Co 1.25%), Monel 400 (Ni 66.5, Cu 31.5, Fe 1.25%, Mn 1.0%), Monel K-500 (Ni 66.5%, Cu 29.5%, Fe 1.0%, Al 2.73%), Carpenter 20Cb-3 (Ni 34.0%, Cr 20.0%, Cu 3.5%, Mo 2.5%, Mn 1.0%), Inconel 600 (Ni 76.0%, Cr 15.5%, Fe 8.0%,), Incoloy 625 (Ni 61.0%, Cr 21.5%, Mo 9.0%, Fe 2.5%, Cb 3.65%), Incoloy 825 (Ni 42.0%, Fe 30.0%, Cr 21.5%, Mo 3.0%, Cu 2.25%, Ti 0.9%). It is preferred the nickel or nickel alloy surface be polished.
Fluoropolymer refers to a fluorinated polymer or copolymer. Any fluoropolymer can be used. Examples of commercially available fluoropolymers include, but are not limited to, polytetrafluoroethylene (Teflon(copyright) PTFE), perfluroalkoxy copolymer (Teflon(copyright) PFA), perfluoro ethylene-propylene copolymer (Teflon(copyright) FEP), ethylene-tetrafluoroethylene (Tefzel(copyright) EFTE), perfluoropolyether such as Krytox(trademark), Kalrez(copyright), Viton(copyright), poly-vinylidine fluoride, fluorosilicones, and combinations of two or more thereof. These fluoropolymers are available from E. I. du Pont de Nemours and Company, Wilmington, Del., U.S.A.